//求四个数当中最大的那个

#include <stdio.h>

float max(float x,float y)
{
	float m;
	m = x > y ? x:y;
	return (m);
}

int main()
{
	float a,b,c,d,m;
	printf("input 4 numbers :\n");
	scanf("%f %f %f %f",&a,&b,&c,&d);
	m =max(max(a,b),max(c,d));
	printf("max = %.3f\n",m);

	return 0 ;
}


